You've seen friends and celebrities post them on Facebook, Instagram and Twitter. You've probably shared one of yourself at some point. There's even two new social networks dedicated to self-portrait photos taken with a smartphone camera.

So it's no surprise that Oxford dictionaries' 2013 word of the year is "selfie."

Britain's Oxford University Press tells The Associated Press that the word "selfie," referring to any photo taken of oneself, exploded in usage in the past year. Editorial director Judy Pearsall said the word was first used in 2002 on an Australian web forum and the hashtag #selfie appeared on photo-sharing site Flickr in 2004.

"But usage wasn't widespread until around 2012, when 'selfie' was being used commonly in mainstream media," she told the AP. The word was first added to its online dictionary in August.

"Selfies" are so popular now that there are even two new websites dedicated to them. Shots of Me, an iOS app partially funded by Justin Bieber, and the aptly-titled Selfie, which only allows users to upload pictures (without filters!) from a front-facing smartphone camera, both launched this fall.

2013's "word of the year" is the same for both the U.S. and U.K. editions of Oxford dictionaries, whereas the publisher typically chooses separate words like "gif" and "omnishambles," respectively, in 2012. Researchers annually choose a word or phrase that reflects the times, such as previous words "unfriend" (2009), "carbon footprint" (2007) and "Sudoku" (2005).

According to Time, "selfie" beat out a number of other popular words this year like "twerk," as in Miley Cyrus' provocative dance moves at the MTV Video Music Awards, and "binge-watch," referring to watching multiple episodes of a TV show on DVD or online streaming.

Here are Oxford's 2013 word of the year finalists and their definitions:

bedroom tax: (n.) a reduction in the amount of housing benefit paid to a claimant if the property they are renting is judged to have more bedrooms than is necessary for the number of the people in the household, according to criteria set down by the UK government.

binge-watch: (v.) to watch multiple episodes of a television program in rapid succession, typically by means of DVDs or digital streaming.

bitcoin: (n.) a digital currency in which transactions can be performed without the need for a central bank. Also, a unit of bitcoin.

olinguito: (n.) a small furry mammal found in mountain forests in Colombia and Ecuador, the smallest member of the raccoon family.

schmeat: (n.) a form of meat produced synthetically from biological tissue.

selfie (n.) a photograph that one has taken of oneself, typically with a smartphone or webcam and uploaded to a social media website.

showrooming: (n.) the practice of visiting a shop or shops in order to examine a product before buying it online at a lower price.

twerk: (v.) dance to popular music in a sexually provocative manner involving thrusting hip movements and a low, squatting stance.

Many of these words were added to Oxford's online edition earlier this year, but "selfie" is also being considered for inclusion in the next edition of the printed Oxford English Dictionary (OED).